Phase 2 study of neoadjuvant cabozantinib in patients with locally advanced non-metastatic clear cell renal cell carcinoma

ABSTRACT

Background: Cabozantinib is a small molecule inhibitor of the tyrosine kinases c-Met, AXL and VEGFR2 that has been shown to reduce tumor growth, metastasis, and angiogenesis. After the promising results from the METEOR, CABOSUN and Checkmate-9ER trials, cabozantinib was approved for use in patients with advanced renal cell carcinoma (RCC). The increased response rates with cabozantinib in metastatic RCC, along with the other neoadjuvant TKI data, support an expanded role for cabozantinib in the neoadjuvant setting. Methods: Patients with clinical stage ≥ T3Nx or TanyN+ or deemed unresectable by the surgeon with biopsy-proven clear cell RCC were eligible for this study, and received cabozantinib at a starting dose of 60 mg daily for 12 weeks. The primary outcome was objective response rate per RECIST v1.1 (complete and partial responses) at week 12 after the administration of cabozantinib as determined by independent radiologist review. Secondary outcomes included safety, tolerability, clinical outcome (DFS, OS), surgical outcome and quality of life. Results: As of 20 September 2021, 16 biopsy-proven clear cell RCC patients were treated with neoadjuvant cabozantinib. The median age was 56 years (range 41-84 years) and 81.2% male. All patients completed 12 weeks of treatment, and 15 of them underwent surgery as planned without any delay after completion of 4 weeks wash-out. One patient refused to undergo surgery due to personal reasons and received further systemic treatment. Five patients (31.2%) experienced a partial response, and 11 patients had stable disease. There was no progression of disease while on cabozantinib. Median reduction of primary renal tumor size was 24% (range 6-45%). The one patient who was deemed to be unresectable became resectable at the end of treatment. Two patients were converted from radical to partial nephrectomy. The most common AEs were diarrhea, nausea, fatigue, hypertension, anorexia, and palmar-plantar erythrodysesthesia syndrome. Intraoperatively, we did not experience any immediate complications. Postoperatively, no surgical complications related to the drug were noted. No treatment related grade 4 or 5 AEs related to cabozantinib or surgery occurred. Two patients had died at the time of analysis (1 due to COVID and 1 unknown cause). Conclusions: Cabozantinib was clinically active and safe in the neoadjuvant setting in patients with locally advanced non-metastatic clear cell RCC. Additional data will be reported including long term outcomes, correlative studies, quality of life, and frailty/sarcopenia indices.